This invention relates to electric switches for controlling electric loads in alternating current supply circuits, and more particularly to an electronically actuated electric switch which is capable of being connected in series with such a load while also utilizing said alternating current supply as the source of power for the switch.
Control of electric loads in alternating current circuits conventionally is afforded by the use of mechanical switches. Typical of such use is the mechanical wall switch which serves to control room lights in residential, commercial and industrial buildings. Mechanical switches also generally are employed throughout industry in the control of electric motors and other electrically operated equipment.
Electro-mechanical and electronically actuated switches provided heretofore for controlling electric loads in alternating current supply circuits all have required an external source of electric power for their operation. This requirement renders such control systems expensive to install and maintain, and renders excessively costly their substitution for mechanical switches.
Although mechanical switches are relatively inexpensive and easy to install, they are subject to wear and malfunction, requiring frequent replacement. Moreover, mechanical and electro-mechanical switches involved the making and the breaking of mechanical contacts and thus are extremely hazardous in use in environments where the presence of combustible gases can result in damaging fires and explosions.